Image processing is important in a wide variety of different machine vision applications, and such processing may involve multiple images of different types, possibly including both two-dimensional (2D) images and three-dimensional (3D) images, obtained from a variety of different image sources. For example, 2D images are provided by image sources such as video cameras and 3D images are provided by depth imagers such as structured light (SL) cameras or time of flight (ToF) cameras. Conventional image processing techniques therefore often require the processing of image streams from multiple distinct sources. However, problems can arise when the different sources generate images at different frame rates.